In microwave technologies, data is directly transmitted through space with no need to lay optical fibers, cables, or the like, which has obvious advantages in engineering in cities, remote areas or special regions such as rivers. The microwave technologies are convenient in networking and flexible in use, and take a short time for service activation. With the development of the microwave technologies, the cost of a microwave equipment is gradually reduced, so that the microwave technologies are more and more widely used.
A power amplifier (PA) is a key component in a microwave communication system, and non-linearity is an inherent feature of the power amplifier. A simplest method for reducing an impact of the non-linearity of the power amplifier on the microwave communication system is to reduce input power of the power amplifier, that is, to perform back-off of the input power of the power amplifier. However, this method reduces maximum transmit power of an outdoor unit (ODU) of the microwave communication system, and also reduces power efficiency of the power amplifier. Another more effective method is a predistortion technology. Besides reducing the impact of the non-linearity of the power amplifier, this method may also raise the maximum transmit power of the ODU of the microwave system, and improve the power amplification efficiency of the power amplifier.
In the predistortion technology in the prior art, a signal received by a microwave receiver is fed back to a microwave transmitter for predistortion computation, and a signal feedback apparatus which is complete from a radio frequency to a baseband needs to be added, so the implementation cost is high.